Staged Left Ventricular Recruitment for Biventricular Conversion in the Borderline Left Heart ChenPeter GreenleafChristopher Dodge-KhatamiAli SalazarJorge 2020 <p>The patient was a 16-month-old female with a diagnosis of Shone’s complex, including hypoplasia of the mitral valve, aortic valve, left ventricle, and aortic arch, and a ventricular septal defect. She had previously undergone single ventricle palliation with a Norwood procedure as a neonate and subsequent bidirectional Glenn procedure at the age of four months. Clinically, the patient displayed appropriate weight gain and energy level and no significant cyanosis or work of breathing.<br></p><p>Preoperative transesophageal echocardiogram demonstrated normal sized right heart structures with a right ventricular ejection fraction of 54% and a diminuitive left heart. The left ventricular ejection fraction was measured at 40%, and the left ventricular end diastolic volume index was 11 ml/m2. The mitral valve annulus measured 8.8 x 6.6 mm, with a Z-score of -3.8, and an inflow gradient of 1-2 mm Hg. The aortic valve was hypoplastic, with no regurgitation and only mild flow acceleration, measuring 8 mm, with a Z-score of -2.4. The atrial septum was wide open measuring 1.2 cm, with a minimal gradient measured across the atrial septum. The preoperative clinical parameters obtained by echocardiogram and MRI are summarized in this slide.</p><p>After redo sternotomy, aortobicaval cannulation was performed. Cardioplegia was administered and the heart was arrested. A right atriotomy was performed, and the mitral valve was inspected across the open atrial septum. The mitral valve was probed and was able to accommodate a 7.5 mm dilator, but unable to accept an 8 mm dilator. A fenestrated atrial septal defect closure was then performed, leaving a 4-5 mm fenestration, which promotes flow through the mitral valve and encourage left ventricular growth over time. A right ventriculotomy was then performed for placement of the right ventricle to pulmonary artery conduit. Right ventricular muscle was resected to prevent any potential obstruction at the proximal RV-PA conduit. A pulmonary arteriotomy was then performed towards the left of the pulmonary artery bifurcation, creating an opening for the distal RV-PA conduit anastomosis. The RV-PA conduit now perfuses the left pulmonary artery, and the right pulmonary artery flow is supplied by the Glenn anastomosis. A 6 mm ringed Goretex graft was then fashioned, and the distal RV-PA anastomosis was performed. The cross clamp was then removed to allow for reperfusion while the proximal RV-PA conduit anastomosis was performed. There is now augmentation of the pulmonary blood flow, and therefore increased pulmonary venous return to the left heart, promoting left ventricular growth. A left atrial pressure monitoring line was placed through the fenestrated atrial septal defect closure to provide hemodynamic data in the immediate postoperative period.</p><p>The postoperative echocardiogram now demonstrated a mean mitral valve inflow gradient of 4-5 mm Hg, secondary to the increased flow across the left heart. Due to the restriction of the atrial septal defect, the gradient across the ASD now measured 7-8 mm Hg. The patient will be followed with serial echocardiograms and cardiac MRI to assess for left ventricular growth and future consideration for completion of the biventricular conversion.</p>